Strand tensioning apparatus



lAug. 12,1947. l E, E, FRANZ 2,425,525

STRAND TENSIONING APPARATUS 33/ I' [,L j I //vE/vronv EE. FRANZ l Arron/ver Mmmm" Aug. 12, E. E. FRANZ l STRAND TENSIONING ArPARATUs Filed Aug. 28, 1945 :e sheets-sheet 2 il l /la z l: l

.l Il Y E.' E., y FRA/vz Arrok/vy' l Patented Aug. 12, 1947 STRAND TEN SIONIN G APPARATUS Erwin E. Franz, Cranford, N. J., assignor to-Western Electric Company Incorporated, New York,

N. Y., a corporation of New York Application August 28, 1945, Serial No. 613,145

6 Claims.

This invention relates to strand tensioning apparatus, andmore particularly to a device for imposing a delicately adjustable constant tension upon a wire or other strand being drawn olf a, stationary spool or reel over one head thereof.

In a great many arts dealing with the treatment or utilization of wires, threads, cords or, in short, material in almost any kind of strand form, the strand to be operated on is drawn from a supply thereof wound on a spool or reel and is often simultaneously subjected to some kind of means resisting the advance of the strand in order to impose a certain predetermined degree of tension upon the strand, required to make the strand follow a prescribed path over guiding and operating elements thereafter. Innumerable devices have been invented or designed for the purpose of thus imposing a constant tension on a strand being drawn through the device against the resistance created thereby. Most frequently such devi-ces depend upon some frictional effect, e. g. a friction brake means acting directly on the advancing strand itself or in a mechanism driven by the advancing strand. The true cause and nature of friction, however, are not yet well understood, although it is known that variation of both the temperature and the moisture content of the immediately circumambient atmosphere tend to affect frictional devices materially and oft unpredictably.

An object of the present invention is to provide means to control the motion of a strand being drawn off a stationary reel over one head of the reel and to eiect a positive and adjustably invariable resistance to the motion of the strand without the employment of any signincant fricticnal effect in the creation of the resistance.

With the above and other objects in view, the invention may be embodied in an apparatus to impose tension on a strand being drawn off over one head of a stationary reel, the said apparatus comprising a strand guide cap member to be supported on the specified head of the reel and to overhang the same peripherally and having a strand guiding surface of revolution coaxial to the axis of the reel, and a flexible annular tension member With a central aperture of diameter intermediate between the maximum and minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member.

Other objects and features of the invention `will appear from the following detailed description of one embodiment thereof, taken in connection with the accompanying drawing in which the same reference numerals are applied to identical parts in the several gures, and in which Fig. l isa broken View in vertical central secv tion of an apparatus constructed in accordance with the invention; l

Fig. 2 is a detached plan view on a reduced scale of details thereof;

Fig. 3 is a broken enlarged sectional View on the line 3-3 of Fig. 1;

Fig. 4 is a view similar to Fig. 1 of amodiiled form; and

Fig. 5 is a'smaller scale, broken view in side elevation of another form.

The apparatus disclosed as an illustrative embodiment of the invention in Figs. 1, 2 and 3, is an arrangement for controlling a Wire HJ being drawn oi from a coiled body II of wire on the barrel I2 of a reel generally indicated at I4 and having upper and lower heads I5 and IB respectively, and an axial tube II.

. The apparatus comprises a can I8 having a cylindrical side wall I9 and a circular iloor 20. In the center of the floor 2U is rigidly secured the lower raceway 2| of a ball bearing unit 22 Whose upperraceway 2li runs on the balls 2-3. In the vcenter of the upper face of the raceway 2l is rigidly secured an upstanding stub 25 whose lower portion is dimensioned to t snugly but not Atightly into the bore of the tube II of the reel I4, as shown, and whose upper portion is preferably ogivally pointed, as shown, to enable thereel to be easily placed down over it.

A reel having been placed in position in this manner, resting its lower head I6 supported on the raceway 24 and positioned coaxially thereon by the stub 25, a cap, generally indicated at 26, is placed resting on the upper head I5 of the reel. The cap 26 comprises a circular disk 2I having an integral (or rigidly attached) rim 28, overhanging the edge of the reel head I5 below and extending upwardly from and around the periphery of the disk 21 as shown. The outer surface of the rim '28 is formed, as shown, so that a strand leading thereto from any part of a layer of strand wound on the reel of average diameter of layers, will come to the surface of the rim 28 substantially tangentially thereto, and will leave the surface of the rim also tangentially when drawn off toward a point in the axis of the spool. The rim 28 is preferably made as hard and as brightly smooth as possible, e. g. with a plated and polished coating of chromium, so that friction on the strand passing thereover is reduced to an unimportant minimum. 'Ihe cap 26 is provided centrally with a depending roundly pointed stub 29 to enter the tube and thereby center the cap on the reel.

A flatly annular tension member 30, whose inner diameter is greater than the minimum diameter of the convex outer surface 'of the rim 28 but less than the maximum diameter of that surface is supportedin position about the rim 28 on the upper annular surface of a cylindrical support 3|, dimensioned to iit down into the can I8 and having on its outer surface a screw thread 32 engaging a corresponding;` thread r3,3' 'on the inner surface of the side wall |9 of the can. Aj

' lowering the member 30, in the manner described,

washer 34 clamps the outer part of the member 30 in place on the support 3|; and the supportV 3|, member 30 and Washer 34 are held together by screws 35. For convenience, the top annular face of the washer may be graduated as indicated in 2-,- and a pointer member 36 may be located on the stationary top of the wall I9 to coact therewith'. Furthermore, a handle 31 may be secured to the top of the support 3| to turn the same in 'the can and thereby raise or lower the support 3| and therewith the annulus'3`li. The member' 30 is made of some iiexibly elastic material, e. g. soft, vulcanized rubber, so Ythat the inner peripheral part of it is both elastically ilexi'ble and elastically extensible. Preferably also, the inner peripheral edge 38 is made toroidal.

Assuming now that a ree-1` I4 ofwire l0 to be unwound is in position as shown', and assuming further that the wire is being drawn upwardly oi the reel toward some point above the reel and in the axis thereof, as indicated in Fig. 1, the ten*- sion member 30 may be dragged down over the rim 28' to some such position as that indicated in broken lines in' Fig, l, by rotating the support 38 with the handle 31. The member 30, by virtue 'of being stretched down 'over the rim 28 holds the latter frictionally against rotation, with respect to itself since the two are 'engaged all around the inner periphery of the member 30.

The rim 28 thusrbeing held against rotation'r and being massive and supported by the'reel I4, holds the latter against rotation with respectV to itself. vThus when the support 3|' is held stationary, 'undercordinary circumstances by themutual fric'-v ltion of Vthe Yscrew threads 3=2 Vand 33-,.the member :39, the cap, 26 and the reel I4 are all held sta;e rtionary on the ball bearing v22 against the rela- :tively slight rotational drag' ofthe strand being drawn off. Con`Verse1y',-Iwhen* the: support 3|is turned in the can by the handleSJ to' raise or lower the support andtherewithV the member 30, the reel mand cap 26 rotate freely on the'bearing 22 aid'there is no relative rotational motion of the member Sil'andrim' 28. Y Y

Asrthe wirev I0 is pulled off the reel u vwardly the wirei advances longitudinally of itself up-` wardly wit-han arc of line contact along thel outer convex'face, of the rim 28; At the same-time, the

wireadvancesy horizontallyV around the rim. AsY

best shown Yin Fig. 3, the inner periphery of the member 3E! lies against the wire inY arcuate. distortion having substantially only very rsmall actual Vcontact with the wire. The member- 30 ,and the rim: 2'8r being stationary, the wire proceeds 'around between them pushing the'disto'rtion laround through the'station'ary susbtance of the elastic member 3.0, and thus doing work on themember 38. It is this'work which offersthe eifec'tive resistance to the motion of the, wire and thus imposes thev desired tension on 'thetwire and thus stretching the, inner periphery thereof less or more severely against the rim 28. Thus the apparatus will impose a tension, continuously adjustably' variable in amount and not in'any material VWay dependent on or affected by any frictional eiect, f

In thearrangement shown in Fig. 4, the member 3|) is mounted directly and non-adjustably on the upper rim of a can H8. In the axis of the 1 can is a threaded shaft or spindle |33,vsupporting a correspondingly threaded sleeve |32 Whichin turn supports a reel IM.V The' wire guide cap is here reduced to the rim |28 alone, formed to rest on the tcp head of the reel. By revolving the rim |28 on its axis, the reel H11A andxsup'port |32 are i forced to rotate on' the spindle |33, and thus are top h eadof the reel. The member 3|) issupported onl the conoid 228` and has its -iouter periphery weighted by can, attached tcro-idal mass V'23|'. Adjustment of tension iseffectedby adding or redue'singA the weight 'applied by placing additional masses 232 on the weight 23| Yor removing the same.

The outer surface ofthe rim A23 'is vshovvnas a..

conoidal surface 'of revolution formedto the vertical curvature of the envelope` of they various `angular positions of :the strand coming te the strand guiding surface from ythe,reelbelow and also going to a varietyV of possible heights of intersection with axisof the reel above Howeverit will be understood that this-is a preferred forma(-V tionof this surface which may be*variouslymodi ned, provided on-ly that an upper circumference ofv less diameter and a lower circ-umferencefof greater diameter are joinedby Yan` intermediate belt which is not concave, i. e. whichmay be convexl-y bulging 'as shown, Vvor could be con-ical instead of @miden .S0` that bye-Menge therelae i' Vtive vertical relation of thewguide rim the gentle' @12ste annales, Sie; thptensen imposing effect di the latter upon 'a strand drawn be Ween them may" te adjdstabiy e'diitinueusiy-yanab1e between a and aimaximum value.` Y

YWhat is claimed is: Y

1.1 Apparatus to` impose tension `onr a strand being drawnoff over oneY head of astationary reel, the Asaid-app aratus comprising a: strand' guide cap member to bersupported on thespecie "head ef the mera-'nd te overhang. the same perte and vhai/'ing fafstrand'gui'ding surfaceofrevo Y coaxial toi meaxisi of trie reel, a flexible annular 'tetisionfme'niber with al centra-l'w diameter intermediate between 'the xnaxixmim and serrure of minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member.

2. Apparatus to impose tension on a strand being drawn off over one head of a stationary reel, the said apparatus comprising a strand guide cap member to be supported on the specied head of the reel and toI overhang the same peripherally and having an upwardly inwardly tapering strand guiding surface of revolution coaxial to the axis of the reel, and a exible annular tension member with a central aperture of diameter intermediate between the maximum and minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member.

3. Apparatus to impose tension on a strand being drawn off over one head of a stationary reel, the said apparatus comprising a strand guide cap member to be supported on the specied head of the reel and to overhang the same peripherally and having a convexly conoidal strand guiding surface of revolution coaxial tothe axis of the reel, and a flexible annular tension member with a central aperture of diameter intermediater between the maximum and minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member.

4. Apparatus to impose tension on a strand being drawn olf over one head of a stationary reel, the said apparatus comprising a strand guide cap member to be supported. on the specified head of the reel and to overhang the same peripherally and having a strand guiding surface of revolution coaxial to the axis of the reel, and a flexible annular tension member with a central aperture of diameter intermediate between the maximum and minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reelv over the strand guiding surface o-f the cap member and under the inner peripheral edge of the tension member,

in combination with means to adjust the relative axial positions of the tension member and cap. 5. Apparatus to impose tension on a strand being drawn off over one head of a stationary reel, the said apparatus comprising a strand guide cap member to Ibe supported on the specified head of the reel and to overhang the same peripherally and having an upwardly inwardly tapering strand guiding surface of revolution coaxial to the axis of the reel, and a flexible annular tension member with a central aperture of diameter intermediate between the maximum and minimum diameter of the cap member to engage coaxially on the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member, in combination with means to adjust the relative axial positions of the tension member and cap.

6. Apparatus to impose tension on a strand being drawn off over one head of a stationary reel, Athe said apparatus comprising a strand guide cap member to be supported on the specied head of the reel and to overhang the same peripherally and having a convexly conoidal strand guiding surface of revolution coaxial to the axis of the reel, and a exible annular tension member with a central aperture o-f diameter intermediate between the maximum and minimum diameter of the cap member to engage coaxially o-n the cap member and to tension a strand drawn from the reel over the strand guiding surface of the cap member and under the inner peripheral edge of the tension member, in combination with means to adjust the relative axial positions of the tension memlber and cap.

ERWIN E. FRANZ.

REFERENCES CITED UNITED STATES PATENTS Name Date Vesey July 21, 1931 Number 

